Detailed Description

lbuild module: modm:platform:core

This module specializes the generic modm:platform:cortex-m module with STM32-specific startup code and linkerscripts.

Startup

The __modm_initialize_platform() callback enables the clock to SYSCFG or AFIO and the clock to all internal SRAMs.

Linkerscript

For each target a specific linkerscript is generated out of a template, which move some sections into special RAMs depending on their purpose. You can place static objects in sections via the modm_section attribute:

Note that the absolute addresses shown here are only for reference and usually differ on a specific device.

Static RAM (SRAM)

The most common memory map consists out of the internal Flash and one or more continuous SRAMs, which are grouped together in one large a CONT_SRAM1 memory. This allows SRAM1 to overflow into SRAM2 and SRAM3 by pushing all sections in front of it further up and collapsing the heap sections. In that case there is no guarantee that the SRAM specific sections (.data_sramN etc) will remain within their original SRAM section, but you can place large objects into higher SRAMs explicitly to free up the space in the lower sections.

Data Core-Coupled RAM (DCCM)

Some STM32F4 have a battery-backed backup SRAM and a single-cycle CCM that is only accessible to the core via the D-Code bus, thus the CCM is not DMA-able. Therefore the main stack is placed into SRAM, even though it is slower than CCM.

Instruction Core-Coupled RAM (ICCM)

Some STM32F3, STM32L4 and STM32G4 devices have a single-cycle CCM that is accessible to the core via the I-Code and D-Code interface. Note that the CCM is not DMA-able.

Tightly-Coupled RAM (TCM)

The STM32F7 devices include an Instruction TCM (ITCM) and a data TCM (DTCM). Note that the DTCM section will overflow into the SRAM1/2 sections.

The STM32H7 memory map is more complex with multiple SRAM regions in seperate power domains D1, D2 and D3. Note that the main .data and .bss sections are placed into the D1_SRAM section because the TCMs can't be accessed by peripheral DMA transfers, but only the MDMA.

Static RAM (SRAM) with vector table remap on F0 devices

This memory map is identical to the SRAM default one, except that .vector_ram is placed at the beginning of SRAM1. It is used on STM32F0 devices in case the platform-specific vector table relocation option modm:platform:core:vector_table_location is set to ram.